Convert Roman numerals to numbers and convert numbers to Roman numerals. Understand Roman numerals letter by letter. Roman numeral converter to convert numbers from 1 to 3,999,999 into Roman numerals.
Roman numerals are a number system developed in ancient Rome where letters represent numbers. The modern use of Roman numerals involves the letters I, V, X, L, C, D, and M.

To convert Roman numerals greater than 3,999 use the table below for converter inputs. Use a leading underline character to input Roman numerals with an overline. A line over a Roman numeral means it is multiplied by 1,000.

Roman Numeral Converter

Formula:
XL = − X (10) + L (50) = 40

For example, to enter overlines

C = 100,000. Enter C into the converter as _C.
CM = 900,000. Enter CM into the converter as _C_M.

1 = I 5 = V 10 = X 100 = C 500 = D 1,000 = M

The largest number you can write in Roman numerals is 3,999 which is MMMCMXCIX. You can represent numbers larger than 3,999 in Roman numerals using an overline. An overline on a Roman numeral means you are multiplying that Roman numeral by 1,000. For the number 50,000 in Roman numerals you would use the Roman numeral L (50) with an overline to make it 50,000.